Category Archives: Ham Radio History

Crosstown Traffic: KC5HWB-Ham Radio’s Forgotten Bands: 220MHz and 900MHz

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Great blog post and discussion from Jason KC5HWB over at the Grapevine Ham Radio blog about 220MHz and 900MHz, the “Forgotten Bands” of ham radio:

When I was first licensed in 1994, the most inexpensive radio I could buy was the Radio Shack HTX-202 mono-band, 2 meter only, 12 memory channel HT. This radio sold brand new in the store for $189. You could also buy the 70 centimeter version of this radio, which had the same memory channels and features, for the same amount of money. Back then, if you wanted a dual-band HT, you were going to spend $300 or more. Today, however, anyone can buy a Chinese dual band for under $50.  20 years ago, if you wanted a 220mhz radio, you’d have to pay several hundred dollars. I don’t remember anything about 900mhz back then, the frequency spectrum belonged to us, but to my recollection there were little to no radios at all.

Today, you can buy a mono-band 1.25 meter radio from Anytone or TYT for under $200. Also, there are many 900mhz radios on the market, most of which are used, but many are obtainable for $100 or less. A good example of this would be the Kenwood TK-981 radio. I constantly see these radios sell used on eBay for $100-$125.

So the question is, why are these two bands forgotten? Today you can get a radio in either of these bands for a decent amount of money, and some people are using them, but they are not nearly as popular as the 2M and 40 bands in amateur radio.  The 1.25 meter band is widely unused in the DFW area, and the band itself, being VHF, could be as reliable as 2 meters.  The 900mhz band is becoming more popular in DFW, but radios are mostly purchased from used markets and surplus of businesses of local government agencies.

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Ham Radio History: The Vibroplex Morse Code key and Carpal Tunnel syndrome in the late 1800s

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Vibroplex “Original Bug” model (picture from Wikimedia Commons)

On Saturdays, I try to visit the weekly Hams and Eggs gathering in Carrollton (please come and join us every Saturday from about 8 AM to 10:30 AM at the Whataburger off the Prresident George Bush Turnpike at the Old Denton exit).  This morning my friend Kevin N5KRG brought in an antique Vibroplex Morse code key and was mentioning a book he had read about this key which has been in continuous production for over 100 years.   The key was developed to help telegraphers avoid “Telegrapher’s Paralysis” or “Glass Arm” syndrome – today we call it “Carpal Tunnel Syndrome.” From a 1997 website titled the Telephraph Office: by Neal McEwen K5RW (from here in the DFW area-I wonder if I’ve met him).

Telegraphers, making the up and down motion on their keys all day, were often the victim of an occupational hazard related to the muscles of the wrist and forearm. Today we call this malady “carpal tunnel syndrome.” In the 19th century it was called “telegrapher’s paralysis” or “glass arm.” To alleviate some of the stress, the “semi-automatic” key was invented at the turn of the century. Today we are more familiar with the name “bug” to describe the semi-automatic key. The “bug” has a lever such that when pushed to one side, the operator can make a dash similar in manner to making a dash on the older style key. When the lever is pushed in the opposite direction, the “bug” makes dots in rapid succession until the operator releases the lever. This action, besides being in the horizontal plane rather than the vertical plan, has reduced significantly, the required manipulation to form the characters of the code.

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Ham Radio History: K3DSM, Roller rinks, and the Autopatch.

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I found this website many years ago by accident when I was doing some research about the old AT&T Long Lines microwave system (My friend owns an old Long Lines concrete tower in Valparaiso, Indiana).  This is the story of Gene Mitchell K3DSM and the trouble he got into with the autopatch on his amateur repeater back in the 1960s.  It’s a good story that unfortunately ends with the loss of his job from AT&T Long Lines because of his “illicit” mobile telephone connection.

Hybrid phone patches were readily available because of this, so this was used to connect the repeater to the phone line. A mechanical phone lift was used to take the phone on and off hook. Soon after the project was working, I found some touchtone equipment at Greybar Electronics and changed over to a touchtone system.

From my house in Merion, I used the tone pulse system while refining the repeater system. The radio range was not great in Merion, but I was able to develop the system and refine it. I moved to Devon in 1967 where I had an excellent high location and converted to UHF (446 & 449 Mhz)

I had a range of 30 to 40 miles and sometimes more from there and the system was impressive. I even bought a used Motorola handie talkie and mounted a touchtone dial to the back of it. This made a very portable wireless system that worked 10 to 20 miles from my house. I could make and answer calls from almost anywhere I went.

I even demonstrated the system to over 300 ham radio operators at a meeting at the GE Space Center in 1970 where 2 ham radio groups (Las Voyagers and Main Line VHF Association) merged to form a larger group (the Philadelphia Area Repeater Association) to build their own autopatch system for all to use on the 2 meter ham band.

What I didn’t mention so far, is that in 1965, I started working for AT&T Long Lines after I graduated from Valpo Tech. Mention of the system at work drew lots of questions and skepticism. The system was simply not understood. Remember now, that connecting anything to your phone line during this period of time was considered taboo. I even went so far as to pay for what was called a coupler from Bell Telephone to try to stay on the up and up.

Everything was great for years until one day, my mobile phone rang while I was waiting for a roller rink to open. As I answered the call, the guy in the car next to me became curious and started asking questions. I explained what I had and how it worked. He then told me what he had. He said he had a device that could call anywhere in the world and that the calls would be free of charge. I listened carefully. The next day, I told my supervisor at work. I also told a ham friend who worked in the district office at AT&T. Both told me it was not possible for him to have such a device or he would be caught.

(Gene Mitchell, K3DSM, http://www.g-c-o.com/k3dsm/repeater.htm)

 

(published from DFW, Texas)